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Java > Open Source Codes > org > apache > ojb > broker > util > sequence > HighLowSequence


1 package org.apache.ojb.broker.util.sequence;
2
3 /* Copyright 2002-2005 The Apache Software Foundation
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 import org.apache.commons.lang.builder.ToStringBuilder;
19 import org.apache.commons.lang.builder.ToStringStyle;
20
21 import java.io.Serializable JavaDoc;
22
23 /**
24  * The HighLowSequence is the persistent part of the {@link SequenceManagerHighLowImpl}.
25  * It makes the maximum reserved key persistently available.
26  *
27  * @version $Id: HighLowSequence.java,v 1.11.2.2 2005/12/21 22:28:41 tomdz Exp $
28  */
29 public class HighLowSequence implements Serializable JavaDoc
30 {
31     static final long serialVersionUID = -2174468157880921393L;
32     private String JavaDoc name;
33     private long maxKey;
34     private int grabSize;
35     private Integer JavaDoc version;
36      // This is not stored in the DB
37 protected long curVal = 0;
38
39     /**
40      * Default constructor for the HighLowSequence object
41      */
42     public HighLowSequence()
43     {
44         // make sure that version column in DB is never 'null'
45 // to avoid problems with
46 this(null, 0, 0, new Integer JavaDoc(0));
47     }
48
49     public HighLowSequence(String JavaDoc tableName, long maxKey, int grabSize, Integer JavaDoc version)
50     {
51         this.name = tableName;
52         this.maxKey = maxKey;
53         this.grabSize = grabSize;
54         this.version = version;
55     }
56
57     public HighLowSequence getCopy()
58     {
59         HighLowSequence result = new HighLowSequence(this.name, this.maxKey, this.grabSize, this.version);
60         result.curVal = this.curVal;
61         return result;
62     }
63
64     public String JavaDoc toString()
65     {
66         ToStringBuilder buf = new ToStringBuilder(this, ToStringStyle.DEFAULT_STYLE);
67         buf.append("name", name).
68                 append("grabSize", grabSize).
69                 append("version", version).
70                 append("maxKey", maxKey).
71                 append("currentKey", curVal);
72         return buf.toString();
73     }
74
75     public Integer JavaDoc getVersion()
76     {
77         return version;
78     }
79
80     public void setVersion(Integer JavaDoc version)
81     {
82         this.version = version;
83     }
84
85     /**
86      * Sets the name attribute of the HighLowSequence object
87      *
88      * @param name The new className value
89      */
90     public void setName(String JavaDoc name)
91     {
92         this.name = name;
93     }
94
95     /**
96      * Sets the grab size attribute of the HighLowSequence object
97      *
98      * @param grabSize The new grabSize value
99      */
100     public void setGrabSize(int grabSize)
101     {
102         this.grabSize = grabSize;
103     }
104
105     /**
106      * Sets the maxKey attribute of the HighLowSequence object
107      *
108      * @param maxKey The new maxKey value
109      */
110     public void setMaxKey(long maxKey)
111     {
112         this.maxKey = maxKey;
113     }
114
115     /**
116      * Gets the name attribute of the HighLowSequence object
117      *
118      * @return The className value
119      */
120     public String JavaDoc getName()
121     {
122         return this.name;
123     }
124
125     /**
126      * Gets the grabSize attribute of the HighLowSequence object
127      *
128      * @return The grabSize value
129      */
130     public int getGrabSize()
131     {
132         return this.grabSize;
133     }
134
135     /**
136      * Gets the next key from this sequence
137      *
138      * @return The next key or 0 if sequence needs to grab new keyset
139      */
140     public long getNextId()
141     {
142         if (curVal == maxKey)
143         {
144             //no reserved IDs, must be reloaded, reserve new keyset and saved
145 return 0;
146         }
147         else
148         {
149             curVal = curVal + 1;
150             return curVal;
151         }
152     }
153
154     /**
155      * Gets the maxKey attribute of the HighLowSequence object
156      *
157      * @return The maxKey value
158      */
159     public long getMaxKey()
160     {
161         return this.maxKey;
162     }
163
164     /**
165      * Grabs the next key set, the sequence must be saved afterwards!!
166      */
167     public void grabNextKeySet()
168     {
169         curVal = maxKey;
170         maxKey = maxKey + grabSize;
171     }
172 }
173
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